DNA Glossary
1. Adenine
A purine base; one of the four molecules containing nitrogen present in the nucleic acids DNA and RNA; designated by letter A. Adenine is one of the two purine nucleobases used in forming nucleotides of the nucleic acids DNA and RNA. In DNA, adenine binds to thymine via two hydrogen bonds to assist in stabilizing the nucleic acid structures. In RNA, adenine binds to uracil, which is used in the cytoplasm for protein synthesis.
2. Allele
One of a series of alternative forms of a gene (or VNTR) at a specific locus in a genome. An allele is any one of a number of viable DNA codings of the same gene (sometimes the term refers to a non-gene sequence) occupying a given locus (position) on a chromosome. An individual's genotype for that gene is the set of alleles it happens to possess. In an organism that has two copies of each of its chromosomes (a diploid organism), two alleles make up the individual's genotype.
3. Allelic Ladder
A mixture of the most common STR alleles that are used to compare with the amplified samples. A size marker containing most or all of the known alleles in a given population, allowing direct comparison with sample DNA.
4. Amelogenin
A PCR amplified locus that varies between males (212 and 218 bp) and females (212 bp only). Amelogenin is a gene-specific, low-molecular-weight protein found in tooth enamel, and it belongs to a family of extracellular matrix (ECM) proteins. Although less than 5% of enamel consists of protein, amelogenins comprise 90% of all enamel protein. The function of amelogenins is believed to be in organizing enamel rods during tooth development. The genes for amelogenin can be used in sex determination of samples from unknown human origin through the Polymerase Chain Reaction (PCR). Mutations in AMELX can cause amelogenesis imperfecta, a disorder of tooth enamel development.
5. AMP-FLP
Polymerase chain reaction amplified restriction fragment lengths polymorphism consisting of variable number tandem repeats.
